Hantavirus Puumala infection as a cause of fever of unknown origin in a child

Hantavirus infection due to Puumala virus causes nephropathica epidemica, a disorder characterized by fever, haematological abnormalities, mild renal dysfunction and ophthalmological abnormalities. The prevalence in most European countries is low, but the virus can be endemic. In children, hantavirus infection is rare. This paper describes a young girl diagnosed with hantavirus infection. The patient presented with high fever, proteinuria, haematuria and eye lesions, but other typical hallmarks of the disease, such as thrombocytopenia and renal dysfunction, were absent. This case report demonstrates the need to consider the diagnosis of hantavirus infection in children with prolonged fever of unknown origin. The diagnosis is based on serological tests.

Human Granulocytic Ehrlichiosis in Belgium: an underestimated cause of disease

OBJECTIVES

Human Granulocytic Ehrlichiosis (HGE) is a recently discovered zoonosis and, in Europe, not always included in laboratory testing when a patient presents with a history of tick bite. The available serology results indicate that HGE should be included in the screening panel when a tick-borne disease is suspected.

METHODS

Serological methods were applied; i.e. indirect immunofluorescence and Western Blot analysis. Sixty-five serum samples from 47 patients were analysed, of six patients sequential samples were available.

RESULTS

33.8% of the submitted samples were found positive in indirect immunofluorescence, Western Blot confirmed 46.1% of these positive samples.

CONCLUSIONS

Although the causative agent and the vector for HGE, Ixodes ticks, are present in Belgium, serology for HGE is seldom solicited. Ehrlichiosis is apparently not always considered as a plausible or possible cause for illness, even when the patient presents with a history of tick bite. We present here a, true be it, incomplete picture of the present situation in Belgium, but nevertheless indicating that it is warranted to test patients with a history of tick bite not only for Lyme disease, but also for HGE.

Rodent host specificity of European hantaviruses: evidence of Puumala virus interspecific spillover

In order to investigate rodent host specificity of European hantaviruses, experimental infection of colonized and wild-trapped rodents was performed. In addition to the natural rodent reservoir, Clethrionomys glareolus, Puumala hantavirus (PUUV) could infect colonized Microtus agrestis and Lemmus sibiricus, but not Syrian hamsters or Balb/C mice. Neither C. glareolus, nor M. agrestis, could be readily infected by Tula hantavirus (TULV). Wild-trapped Apodemus flavicollis and A. agrarius, the natural reservoirs of Dobrava (DOBV) and Saaremaa (SAAV) hantaviruses, respectively, could both be infected by SAAV. NMRI mice could also be infected by SAAV, but with lower efficiency as compared to Apodemus mice. Balb/C and NMRI laboratory mice, but not C. glareolus, could be infected by DOBV. To our knowledge, this is the first time DOBV and SAAV have been shown to infect adult laboratory mice. Moreover, potential hantavirus spillover infections were investigated in wild-trapped rodents. In addition to the natural host C. glareolus, we also found M. arvalis and A. sylvaticus with a history of PUUV infection. We did not find any C. glareolus or A. sylvaticus infected with TULV, a hantavirus which is known to circulate in the same geographical regions of Belgium.

Distribution of hantavirus foci in Belgium

During 1999 and 2000, we performed rodent captures on 15 sites all over Belgium to evaluate the presence of hantaviruses in local rodent populations. Viral antibody and RNA detection was performed by ELISA/focus reduction neutralisation test and RT-PCR, respectively. We found hantavirus-positive rodents on 13 out of 15 trapping sites and 3 rodent species were found positive for hantavirus infection. Apart from Puumala virus that was carried by Clethrionomys glareolus, 2 additional rodent species, Microtus arvalis and Apodemus sylvaticus, were found antibody- and/or RNA-positive.

Seroprevalence of human granulocytic ehrlichiosis infection in Belgium

In order to determine the prevalence of human granulocytic ehrlichiosis (HGE) in Belgium, the sera of 216 patients previously diagnosed with Borrelia burgdorferi infection were analysed for possible coinfection with the agent of HGE. For this purpose, an indirect immunofluorescence assay was applied, and positive results were confirmed by Western blot using a 44-kilodalton recombinant protein (rP44) specific for the agent of HGE. Sixteen of the 216 (7.4%) sera tested were positive for the HGE agent using indirect immunofluorescence assay, and seven (3%) of them were confirmed positive by Western blot. These data suggest the agent for HGE is present in Belgium and may cause coinfection in patients infected with Borrelia burgdorferi, as has been reported in the USA and elsewhere in Europe. This is the first report documenting the identification of this agent in Belgium.

Tula hantavirus in Belgium

European common voles (Microtus arvalis), captured in Belgium in 1999, were proven by molecular as well as by serological techniques to be infected with Tula hantavirus (TULV). This is the first evidence for the presence of TULV in this country. No indication of spill-over infections of Puumala virus, known to be highly endemic among bank voles (Clethrionomys glareolus) within the same geographical regions as the trapped TULV-infected common voles, was observed. Together with previous reports on the circulation of TULV in eastern/central Europe, this finding suggests a more wide-spread circulation of this hantavirus serotype throughout the continent.

Tula virus infection associated with fever and exanthema after a wild rodent bite

Reported here is the first case of human acute infection with Tula virus, which occurred in a 12-year-old boy in Switzerland. This hantavirus had been considered apathogenic to humans, and in Switzerland only TULV-genome sequences have been demonstrated in wild rodents to date. In this case, paronychia, fever and exanthema occurred after the patient was bitten by a wild rodent, indicating an unusual route of hantavirus transmission. Thus, Tula virus infection should be taken into account in patients with appropriate clinical symptoms and contact with rodents.

The assessment of human health risks from rodent-borne diseases by means of ecological studies of rodent reservoirs

Zoonoses in general, and more specifically rodent-borne diseases, have proven to be of increasing importance in recent decades. The study of vector biology, therefore, is the foundation for understanding the infection mechanisms for humans. Military operations on the European and Asian continent have been substantially affected by Hantavirus infections during World War I and World War II, the Korean War, and the more recent events in Bosnia. The recently discovered Hantavirus serotypes with high mortality may extend the risk for the future to North America. In this article, we focus on the host and ecosystem relationships that might be useful in predicting potential outbreaks in Western Europe.

Incidence of hantavirus infections in Belgium

Over the last two decades, and from the moment that serological detection was possible, human hantavirus infections have been documented in most European countries. This paper summarises the available data on hantavirus cases in Belgium. These data enable the demonstration of the existence of a 3-year epidemic cycle in Belgium, which is apparently linked to rodent population dynamics.

Genetic characterization of Puumala hantavirus strains from Belgium: evidence for a distinct phylogenetic lineage

Puumala hantavirus (PUUV) sequences were recovered from red bank voles (Clethrionomys glareolus) trapped between 1996 and 1998 in four localities of southern Belgium: Thuin, Montbliart, Momignies and Couvin. In addition, three PUUV isolates originating from bank voles trapped in the 1980s in southern (Montbliart) and northern (Turnhout) Belgium were genetically characterized. Analysis of the complete S and partial M segment sequences showed that the Belgian PUUV strains constitute a genetic lineage, distinct from other known PUUV lineages from Europe and Japan. This lineage also includes a wild strain (Cg-Erft) originating from a neighbouring area of Germany. Within the Belgian lineage, geographical clustering of genetic variants was observed. In the Montbliart site, the range of diversity between the most temporally distant strains (from 1986 and 1996-1998) was higher than between those from 1996 and 1998, suggesting slight genetic drift via accumulation of neutral or quasi-neutral substitutions with time.

Spatial and temporal dynamics of Puumala hantavirus infection in red bank vole (Clethrionomys glareolus) populations in Belgium

Dynamics of hantavirus infection and population densities in rodents were investigated from 1996 to 1999 in southern Belgium. Evidence of Puumala infection was restricted to Clethrionomys glareolus. Although the serotype was not determined, antibodies against hantavirus were also found in eight Apodemus sylvaticus. In fall 1996, the seroprevalence in C. glareolus was high (20.1%, 37 of 184) and the infection was widely distributed in the area studied whereas a focal occurrence of positive rodents and lower seroprevalence rates were recorded in spring 1997 (14.3%, six of 42), fall 1997 (6. 6%, 11 of 166), spring 1998 (6.4%, three of 47) and fall 1998 (6.7%, 11 of 165). A pullulation of rodents was observed in spring 1999 and was associated with a markedly higher seroprevalence in C. glareolus (47.7%, 189 of 396). In all seasons, infection rates in adults were higher than in juveniles and subadults. No significant difference of prevalence was recorded between males and females. In two trapping sites, the temporary disappearance of positive animals after a crash in rodent populations suggests that a threshold in density is necessary for the maintenance of the enzootic cycle.

A major outbreak of hantavirus infection in Belgium in 1995 and 1996

Haemorrhagic fever with renal syndrome (HFRS) is a human disease characterized by flu-like symptoms, renal dysfunction, and in severe cases, haemorrhagic manifestations. The causative agents of HFRS are Hantaan (HTN), Seoul (SEO), Puumala (PUU) and Dobrava (DOB) hantaviruses. Hantavirus infections are of increasing importance in Europe. Outbreaks occur in Belgium with a 3- to 4-year interval with an increasing number of cases. We describe the largest outbreak so far in Belgium with 217 serologically and clinically confirmed cases in the period between October 1995 and December 1996. We demonstrated that the use of viral antigen derived from a local PUU-strain was able to detect significantly more sera positive for IgM in an immunofluorescence assay. Furthermore, although in some cases SEO, HTN and DOB antibody-reactivities were detected by ELISA, only PUU infections could be confirmed by neutralization test. The presence of an unknown hantavirus serotype circulating in Belgium should be considered.

The hantaviruses of Europe: from the bedside to the bench

In Europe, hantavirus disease can hardly be called an emerging zoonosis; it is rather a rediscovered disease. Since 1934 an epidemic condition with primarily renal involvement has been described in Sweden. Nowadays, hundreds to thousands of cases per year are registered in Fennoscandia, fluctuating with the numbers of the specific Arvicoline-rodent reservoir, the red bank vole, which carries the main European serotype, Puumala (PUU). In the early 1980s, the rat-transmitted serotype, Seoul (SEO), caused laboratory outbreaks throughout Europe, and recent reports also suggest sporadic, wild rat-spread hantavirus disease. In the Balkans, at least four serotypes are present simultaneously: PUU, SEO, the "Korean" prototype Hantaan (HTN) or HTN-like types, and Dobrava, the latter causing a mortality rate of up to 20%. Moreover, recent genotyping studies have disclosed several PUU-like genotypes spread in Europe and/or Russia by other genera of the Arvicoline-rodent subfamily: Tula, Tobetsu, Khabarovsk, and Topografov. Their importance for human pathogenicity is still unclear, but serologic cross-reactions with PUU antigen might have caused their misdiagnosis as PUU-infections in the past.

Injuries of the ulnar collateral ligament of the thumb metacarpophalangeal joint. Biomechanical and prospective clinical studies on the usefulness of valgus stress testing

In an effort to determine whether valgus stress testing of the thumb metacarpophalangeal joint is predictive of a torn and displaced ulnar collateral ligament, anatomic and prospective clinical studies were performed and the results correlated. In the anatomic study on autopsy specimens, dividing the proper collateral ligament resulted in a significant increase in valgus instability of the flexed metacarpophalangeal joint. Significantly less laxity was noted when the joint was tested in extension. When the accessory collateral ligament/palmar plate complex was also divided, valgus instability in extension increased to the extent that it no longer differed significantly from the values obtained when the joint was tested in 30 degrees flexion. In the clinical study, valgus instability of greater than 35 degrees when the joint was positioned in extension and then stressed consistently indicated the presence of tears of the proper and accessory collateral ligaments: A Stener's lesion was present in 15 of 17 such cases (87%). Values on valgus stress testing of the metacarpophalangeal joint in extension and 30 degrees flexion are highly predictive of both disruption and displacement of the ulnar collateral ligament of the thumb.

Ontogeny of cholecystokinin receptors in the human striatum

The distribution of cholecystokinin binding sites was studied by receptor autoradiography in the human striatum at midgestation, birth and adulthood. In the adult, cholecystokinin receptors are inhomogeneously distributed with patches of reduced labeling. In the caudate nucleus but not in the putamen these patches match the striosomal organization as revealed by acetylcholinesterase staining. At midgestation, patches of high density of cholecystokinin receptors are in register with the dopamine D1 receptor-enriched striosomes. At birth, this striosomal organization has already evolved into the adult pattern of higher matrix level in contrast to the striosomal pattern of acetylcholinesterase staining.

Intercalary flexor tendon grafts. A morphological study of intrasynovial and extrasynovial donor tendons

Intercalary intrasynovial and extrasynovial flexor tendon graft donors were placed within the synovial sheaths of the medial and lateral forepaw digits of 22 dogs and treated with early controlled passive mobilization. Specimens were studied by light and transmission electron microscopy at 10 and 21 days. Early repair in the extrasynovial tendons occurred by an ingrowth of connective tissue from the digital sheath. Adhesions obliterated the gliding surface and occupied the space between the tendon's gliding surface and surrounding tissues. There was no epitenon response noted in the extrasynovial tendon grafts. While there was considerable new collagen fibril formation within the repair site at the ultrastructural level, there was a lack of longitudinal remodeling. In contrast, the intrasynovial tendon grafts showed early healing, with minimal adhesion formation, by a proliferation and migration of cells from the epitenon. These cells showed greater cellular activity and collagen production at 10 and 21 days compared to cells in extrasynovial tendons at the same intervals. The findings of this study suggest that the use of intrasynovial autogenous tendon graft donors, coupled with early controlled motion, stimulates an intrinsic repair process in both the tendon stump and autogeneous tendon graft. These findings differ significantly from the experimental findings in which extrasynovial, paratenon-covered grafts are used.

Thermal survival characteristics of cell subpopulations isolated from a heterogeneous human colon tumor

Responses of a heterogeneous human colon adenocarcinoma model tumor system to in vitro hyperthermic treatment at various temperatures have been studied. This model tumor system consists of an original tumor line (DLD-1) obtained from surgical biopsy, and two derivative subpopulations termed clones A and D. These 3 tumor cell populations differ in many properties, including karyotype and DNA content, production of specific antigens, and sensitivities to other cytotoxic agents such as chemotherapeutic drugs and X-irradiation. In these experiments, exponentially growing tumor cells were exposed to hyperthermia (42.2, 42.5, 43.0, 44.0, or 45.0 degrees) for graded time periods. A single-hit, multitarget equation was used to express the dependence of survival on time at a given temperature, and values for extrapolation numbers, quasi-threshold time (min), and T0 (mean lethal time; min) were obtained for the initial regions of survival. At the lower temperatures of 42.2 and 42.5 degrees, biphasic survival curves were obtained for all three tumor lines and, as a consequence, a second mean lethal time (T0,f) was also determined for the final thermal-resistant portion of the survival curves. Using the T0 values as an index of relative resistance, values at 42.2 and 42.5 degrees indicated that, in this temperature region, the parent (DLD-1) line was the most sensitive, the clone A line showed intermediate sensitivity, and the clone D line was the most resistant. In the thermally resistant portion of the survival curve, T0 values indicated that the clone A subpopulation was the most sensitive, the DLD-1 line showed intermediate sensitivity, and the clone D tumor subpopulation remained the most resistant. At the higher temperatures of 43, 44, and 45 degrees, in which thermotolerance is not observed during heat treatment, values for T0 indicated the parent (DLD-1) tumor line was still the most sensitive tumor line, and the clone A and clone D lines showed approximately equal resistance. These data indicate that significant differences may exist among subpopulations of heterogeneous tumors in their survival responses to hyperthermia.

Survival responses of cell subpopulations isolated from a heterogeneous human colon tumour after combinations of hyperthermia and X-irradiation

In summary, this research has investigated the effects of combined modality treatment (i.e., low linear energy transfer ionizing radiation and hyperthermia at 42.5 degrees C) on the survival responses of two tumour subpopulations (designated clones A and D) obtained from a heterogeneous human colon adenocarcinoma. A constant hyperthermic exposure (2 hours at 42.5 degrees C) was given either 3 min before or 3 min after graded exposure to X-rays. An isobologram analysis (Steel and Peckham 1979) of the clonogenic survival responses of the two tumour subpopulations showed that the clone A responses were within the envelope of additivity for either sequence of application. In contrast, the responses of the clone D tumour subpopulation exhibited a supra-additive response to the combined treatments with the sequence of heat followed by X-irradiation being somewhat more effective than the sequence of X-irradiation followed by heat. These data indicate that the responses of tumour subpopulations obtained from heterogeneous solid tumours to combined modality treatments may vary in an, at present, unpredictable manner.